In recent years, emergency response systems have come into widespread use in the United States. If not already in existence, emergency response systems are likely to become widely used in other countries of the world. As a matter of fact, several Western European countries already have emergency response systems.
In an emergency response system, emergency calls are made by dialing a specific emergency code--911 in the United States and 999 in Western Europe. The calls are routed to an emergency response center, denoted a public safety answering point ("PSAP") in the U.S. In the U.S., basic 911 service merely provides routing of 911 service calls to the PSAP serving the subscribing community. Enhanced 911 service drastically improves basic 911 service. Enhanced 911 service provides automatic number identification ("ANI") and automatic location identification ("ALI"), in addition to selectively routing emergency response, i.e., 911, calls to PSAPs. With ANI, a 911 dispatcher receives a visual display of the telephone number associated with the telephone that originated the 911 call. With ALI, the dispatcher also receives a visual display of the name and address associated with the calling telephone number. Obviously, the extra information aids in promptly responding to the emergency.
Unfortunately, present enhanced 911 emergency response systems have two major disadvantages. One disadvantage is the cost of operating such a system. The cost is prohibitive for many small communities with the United States. The second disadvantage is the difficulty in identifying the exact location of the telephone that placed a 911 call in all circumstances.
Enhanced 911 emergency response system costs can be broken down into two categories. The first category is the cost of the equipment necessary to establish the system. Overall, this cost is relatively minimal. The major cost of an enhanced 911 emergency response system is the ongoing cost associated with obtaining and maintaining a database that includes current address information. At the present time, regional organizations provide location identification information to local communities that operate 911 enhanced emergency response systems. Obviously, a massive effort is required to maintain address information current. Address information is maintained in regional reverse directories operated by regional organizations owned by a large telephone company or a subsidiary of a large telephone company. When a 911 call is made, the regional reverse directories are either automatically accessed or manually accessed by a local community 911 dispatcher, via a long distance telephone line. Regardless of how accessed, the telephone number of the telephone that placed the 911 call causes the reverse directory to generate address information, which is displayed on the 911 dispatcher's console. Because regional reverse directories are expensive to maintain, the access charges to local communities providing enhanced 911 emergency response service are relatively high.
In addition to being expensive to maintain, regional reverse directories are not always as accurate as desired. More specifically, as noted above, at present, when a 911 call is placed, an enhanced 911 emergency response system automatically routes the call to a regional center, as well as to a 911 dispatcher. By means of a reverse directory, the regional center determines the address of the call and sends this information to the 911 dispatcher. The address provided by the reverse directory is usually the billing address of the associated telephone number, which may not be the same as the physical location of the telephone that placed the 911 call. While, in most residence situations, residence addresses correspond to billing addresses, in many business situations, telephone locations may be a great distance from the associated billing address. While this may be due to the use of private branch exchanges ("PBXs"), it is often done for accounts payable reasons. Likewise, telephone locations may be a great distance from the associated billing address in the case of telephone number resellers for apartments, condominiums, office buildings, and institutions. The difference between telephone location and billing address can result in confusion and delay by police, fire, emergency medical personnel and the like attempting to respond to a 911 caller's needs.
Consequently, there exists a need for a low cost emergency response system that provides extremely accurate telephone location information to an emergency response dispatcher. The present invention is directed to fulfilling this need.